Overview

This is a randomized, double-blind, placebo-controlled, multicenter, 28-day study of adult participants hospitalized with COVID-19, with a safety follow-up telephone call at Day 60.

Eligibility

Inclusion Criteria:

• Signed and dated informed consent document(s).
• Agrees to the collection of nasopharyngeal swabs and venous blood and all other protocol-specified procedures.
• Male or non-pregnant female adult 18 years of age at time of enrollment.
• Hospitalized and has laboratory-confirmed infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
• Symptom onset was 7 days prior to enrollment.
• Has oxygen saturation SpO2 <94% on room air.
• Fever with temperature of 36.7 Celsius () axilla, 38.0 oral, or 38.6C tympanic or rectal.
• Has at least one of a respiratory rate >24 breaths/minute or cough.
• Lung involvement as confirmed by radiographic infiltrates observed on imaging (chest X-ray, computed tomography (CT) scan, or an equivalent test).
• Women of childbearing potential must have a negative pregnancy test at screening and agree to abstinence or the use at least one primary form of contraception for the duration of the study following discharge from the hospital, and for up to 50 days after the last dose of study drug (acceptable methods will be determined by the site).
• Men sexually active with women of childbearing potential who have not had a vasectomy must agree to use a barrier method of birth control during the study following discharge from the hospital and for up to 50 days after the last dose of study drug.

Exclusion Criteria:

• Requires mechanical ventilation.
• Current participation in any other clinical study.
• Alanine transaminase/aspartate transaminase levels 3 times the upper limit of normal (ULN) or total bilirubin (Tbili) 2ULN.
• Lymphocyte count <1000 lymphocytes/microliter (L) or hemoglobin <12.0 grams/deciliter (g/dL) in women or <13.5 g/dL in men.
• Stage 4 severe chronic kidney disease or requiring dialysis (that is, estimated glomerular filtration rate <30).
• Any other condition, that in the opinion of the Investigator, may be cause to exclude the participant from the study.
• Use of steroids, sensitive CYP2D6 substrates, CYP2C inducers, IL-6 neutralizing antibodies, IL-6 receptor inhibitors, or any investigational therapy.
• Pregnancy or breast feeding.
• Anticipated transfer to another hospital which is not a study site within 72 hours.
• Known allergy to PTC299 or excipients.